(783) Delayed Oral Misoprostol Dosing for Cervical Ripening: association with perinatal outcomes

Friday, January 31, 2025

10:30 AM – 12:30 PM

Presenting Author(s)

Suna Njie, MD

Kaiser Permanente Northern California
Oakland, CA, United States

Coauthor(s)

FX

Fei Xu, MS

Kaiser Permanente Northern California
Pleasanton, California, United States

Submitting Author(s)

JB

Jennifer M. Baker, MPH

Research Project Manager
Kaiser Permanente Northern California
Pleasanton, California, United States

Coauthor(s)

MK

Michael W. Kuzniewicz, MD, MPH

Kaiser Permanente Northern California
Kaiser Permanente Northern California, California, United States
Monique Hedderson, PhD

Associate Director, Women’s and Children’s Health Section. Director of Research Clinics
Kaiser Permanente Northern California
Pleasanton, California, United States
Mara Greenberg, MD (she/her/hers)

Clinical and Research Director, Regional Perinatal Service Center
Kaiser-Permanente Northern California
Oakland, California, United States

Objective: To examine dosing characteristics for misoprostol used as a cervical ripening agent in a large integrated health care system and evaluate association between dosing delay and perinatal outcomes.

Study Design: Retrospective study of all deliveries without prior cesarean that underwent induction of labor (IOL) from 2011-2023 at Kaiser Permanente Northern California. For the proportion of patients undergoing IOL who received misoprostol for cervical ripening, dosing characteristics were examined. Delayed dosing among patients who received >1 misoprostol dose was defined as >4.5 hours between doses. Associations between delay characteristics and outcomes including cesarean delivery, chorioamnionitis, postpartum hemorrhage, time to vaginal delivery, and length of stay were examined in unadjusted and multivariable analyses.

Results: Among 126,864 induced labors without prior cesareans, 91,776 (72%) received misoprostol and of those 53,734 (58.6%) received >1 dose. Most misoprostol was dosed orally (96.7%) starting with an initial dose of 50mcg (98.8%), and subsequent doses of 100mcg (95%). Delayed dosing was present in 55.6% (29,863), and of those with delays 41% were delayed within 1 hour, 19% from 1-2 hours and 40% >2 hours. Delay in misoprostol dosing was associated in a dose response manner with perinatal outcomes (Figure 1), with higher degrees of delay associated with higher rates of cesarean delivery, chorioamnionitis, and postpartum hemorrhage, lower rate of achieving vaginal delivery within 24 hours, and longer length of stay. In multivariable analysis, presence and degree of dosing delays were associated with increased adjusted risks of all adverse outcomes examined (Table 1).

Conclusion: Delayed oral misoprostol dosing was common in a large diverse cohort of induced labors. Frequency and degree of dosing delay was associated with adverse perinatal outcomes. This presents a potential opportunity to improve quality of intrapartum care and outcomes of labor.